QMail Not Rejecting nonexistent user

[vbfischer]

In my Plesk, I have:

<domain> -> Mail -> Mail to nonexistent user set to "Reject"

However, if I try to send an email to a user that doesn't exist (from another email account on another server) I get a bounce message:

Unknown user: [email protected]x

RCPT TO generated following response:
550 sorry, no mailbox here by that name. (#5.7.17)

 

[vbfischer]

I just realized that its probably the MTA's server that is reporting the error, not a bounced message.